With only a matter of days to go before the Information Commissioner rules on the disclosure of West Ham’s Olympic Stadium deal, park bosses insist they are right to keep parts of the deal with the club secret.

London Legacy Development Corporation appealed against the commissioner’s order in January that the details of lucrative contract be put in the public domain. They now await his verdict “in the next couple of weeks”.

The controversy gathered momentum when it was revealed that the stadium operators had extended the club an extraordinary level of support, including ground maintenance, corner flags and security – all bills that a football club would ordinarily pay. The club won’t even have to buy their own goalposts at the £700million Stratford showpiece.

Answering the persistent criticisms of the London Assembly, LLDC chief executive David Goldstone said this week he had a duty to maintain the long-term viability of the stadium. Surrendering information about the deal, he said, would give competitors an edge for years to come and shortchange the tax payer as a result.

In a fractious series of exchanges at City Hall, Assembly member Len Duvall accused Mr Goldstone of “dodging and swerving” around the issue.

Mr Goldstone pointed out that the LLDC had released the deal in its entirety except for “three specific clauses”.

“We are doing this on the basis of very strong legal advice that it is the right thing to do on the grounds not doing so would put our commercial position at a disadvantage and to the disadvantage of tax payers whose money we are managing.

“We received unambiguous advice that the appeal was warranted and if we didn’t do appeal the board would be being irresponsible in terms of the potential hundreds of millions of pounds over a 99-year period we could be putting at risk.”

He was told that he could expect “99 years of questions” from the Assembly.

Cheikhou Kouyate, Pedro Obiang and Sam Howes take a break from installing seats

LLDC chairman David Edmonds said: “We wanted at the heart of the park a thriving successful stadium to get that we went into a competitive situation that West Ham won.

“We’ve now got a thriving football club playing 25-30 matches a year providing a real heart to the Olympic Park . There are some downsides but we profoundly believe that having got the deal, having got a multi-use stadium, having the Premier League is an important part of the park development.”

Meanwhile the LLDC has cleared up the background to a dispute about ground sharing. West Ham vice-chairman Karren Brady had said the club would “probably say no” to a ground share with Tottenham, which prompted a question over why West Ham had a veto.

Mr Edmonds explained Premier League rules meant that West Ham would have to agree to a ground share even though a decision would be taken jointly between the LLDC, West Ham and the Premier League.

He said: “There is no veto right but the Premier Leagues suggest both sides would have to agree.”